The present disclosure generally relates to noise cancelling devices, systems, and methods, specifically to anti-snoring systems and methods producing anti-noise.
Low-frequency noise pollution, such as that caused by snoring, has long been a bane of people sleeping in proximity to one another, such as when sleepers share a bed, room, or are seated in close proximity to one another in transportation settings such as on an airplane. Additionally, other ambient noise such as sirens, traffic, crying babies, and televisions can cause disruptions in sleeping. Snoring, in particular is credited with sleep disruption of a significant portion of sleepers.
Snoring is an acoustic phenomenon generated by vibrating tissue structures due to obstruction in the upper airway during sleep, and is a prominent problem in modern society. Some references, including the U.S. National Commission on Sleep Disorders Research, estimate that about 74 million Americans snore every night, and about 38% of Americans are disturbed by snoring and suffer from daytime fatigue. The intermittent nature of snoring can disrupt the sleep of the snorer's bed partner, causing stress and social nuisance. The sleep disruption has been linked to excessive daytime sleepiness of the snorer and their bed partner. This can result in loss of productivity in the work environment and lead to occupational accidents, or even reduce one's ability to safely operate a car. As mentioned, snore sounds are typically generated by vibrations of the soft palate during sleep and often are nonstationary, intermittent, complex sounds having a transient nature and high short-term sound levels. Additionally, frequency content of snore sounds can change abruptly. As such, actively modeling and canceling snore sounds is difficult.
For low-frequency snoring and other environmental noise, passive methods such as earmuffs or earplugs are either ineffective or uncomfortable to wear during sleep. Several noise cancellation methods have been developed to reduce the noise of snoring utilizing active noise control (referred to herein as “ANC”). These ANC systems are typically based on the principle of super positioning opposing phased sounds to attenuate low-frequency primary (unwanted) noise. That is, ANC systems typically generate a secondary noise of the same magnitude but opposite polarity as the noise sought to be cancelled. As used herein, this secondary noise of the same magnitude but opposite polarity is referred to as “anti-noise.” By ANC, the anti-noise and the unwanted noise are both canceled out or their sound pressure level (SPL) is greatly reduced.
For example, ANC systems for abating snoring and other environmental noises have been disclosed. For example, U.S. Pat. No. 8,325,934 to Kuo et al. entitled “Electronic pillow for abating snoring/environmental noises, hands-free communications, and non-invasive monitoring and recording” describes such systems and is incorporated herein by reference in its entirety. Additional systems are described by Sen M. Kuo, et al., in “Active snore noise control systems,” which is published in the January-February, 2008 issue of Noise Control Engineering Journal, volume 56(1), which is incorporated herein by reference in its entirety. These systems, however, suffer from several drawbacks, including, among other things, anti-noise speakers that are mounted in less-than-ideal positions as well as the need to have pillows and other bedding units hard-wired to external system components and even other pillows and bedding units. Moreover, ANC systems typically implement dynamic adjustments of anti-noise. These prior art dynamic adjustments cause the systems to converge toward ineffective ANC at least because the dynamic adjustments fail to properly account for periods where no ambient noise is detected, such as in between snores.
Accordingly, there remains a need for improved systems, devices, and methods of abating snoring and other environmental sounds in a sleeping system.